Anna Wintour and Tom Ford slipped through the discreet door in the heart of Mayfair early.

An hour later, Cameron Diaz dashed in without a backward glance, closely followed by Gwyneth Paltrow, who paused reluctantly on the doorstep to give the cameras a split-second pose and pained grin.

And that was the sum excitement for star-spotters waiting on the pavement outside the Obama Victory Fundraising dinner in London on Wednesday.

Hosted by Paltrow, Wintour and Ford at the exclusive Mark's club, the minimalist guest list saw fewer than 25 people hop from their black cabs and chauffeur-driven cars into the club.

Natalie Massenet, founder of Net-a-Porter and new chair of the British Fashion Council was there – albeit wearing Yves Saint Laurent – as was Downton Abbey's Elizabeth McGovern and Elizabeth Saltzman, international social editor of Vanity Fair.

The hedge fund managers and property investors crowded onto the pavement of the pub opposite the club barely registered the small stream of other more anonymous guests, dressed in a range of diplomatically restrained black dresses and perfectly cut suits.

As one woman protested, stumbling in the glare of the flashlights as she fumbled for ID to show the woman guarding the door: "I'm no one famous."

Journalists were strictly forbidden from attending the event – the hosts, perhaps, fearing a Romney-shaped uproar if remarks intended only for the ears of wealthy campaign donors reached the public.

But if the night was bijou, then that is how Wintour intended it. This was the fourth fundraising event the editor of Vogue has hosted this year. By last month, she had already donated the maximum allowable $35,000 to the Obama Victory Fund and the Democratic National Committee, Obama's candidate committee.

The guests, it is said, paid $15,000 to rub shoulders with the small band of stars from fashion and film. The hosts paid $40,000 to the president's campaign coffers.

This is the first fundraiser Paltrow and Ford have hosted, although both have been active donors to the Democratic campaign. According to the Sunlight Foundation's Influence Explorer, Paltrow has given $20,000 to the Obama Victory Fund. Ford has donated £75,000 to Obama for America.